The IRSET18 has an 18" Precision Marking Rule, T-Rule, and Bend Rule. With the pencil in a marking hole on the T-Rule, slide along any edge to draw perfectly placed horizontal lines Use as a precision T-Square to draw perpendicular lines T-bar is easily adjusted for making fast vertical measurements Micro-fine guide holes and slots at every 1/16", 1/32" and 1/64" scale position instantly locate your sharp pencil or scribe at the exact measurement with zero uncertainty and no eye strain! The Marking Rule and Bend Rule have micro-fine guide holes at every 1/32" and slots at every 1/16".